For those with few skills but plenty of enthusiasm, try AndroVid. It's really simple to use and free if you can deal with ads. There are various ways to jazz up your video: combine short clips, add text, add a soundtrack. Clear and simple controls, it's great for novice users.

Got an Apple device? iMovie is super easy to use, though customizing the trailer templates is not. If you like the templates, great. If you like one well enough, you can start in the trailer template and convert the project to a movie to get greater control over fonts and music tracks.

Whatever you choose, take a few hours, invest the time and make a trailer! Give your readers (or potential readers) a glimpse of what your epic tale is about.